1. Field of the Invention
The present invention relates to an apparatus for producing single crystals grown by the Czochralski (CZ) method also known as the pulling method. More particularly, it relates to such an apparatus which is capable of protecting a Czochralski-grown single crystal from contamination with metal while the single crystal is pulled by a flexible pulling means such as a pull wire.
2. Description of the Prior Art
In apparatus for producing Czochralski-grown single crystals and single crystal silicons, in particular, a pulling mechanism generally comprises of a winding mechanism including a flexible pulling means such as a pull wire. Regarding the winding mechanism, various attempts have been proposed, as disclosed in Japanese Patent Laid-open Publication Nos. 57-27997, 57-118088 and 62-65994.
All such known winding mechanisms include a power transmission mechanism, composed of a gear mechanism or a pulley mechanism, and a bearing mechanism that are disposed in a winding portion or unit which is kept under the same condition as the furnace atmosphere. These mechanisms necessarily constitute a dust-generating source which will contaminate a Czochralski-grown single crystal with metal.